Solve for $x$ and $y$ using substitution. ${4x-3y = -1}$ ${y = 3x-3}$
Solution: Since $y$ has already been solved for, substitute $3x-3$ for $y$ in the first equation. ${4x - 3}{(3x-3)}{= -1}$ Simplify and solve for $x$ $4x-9x + 9 = -1$ $-5x+9 = -1$ $-5x+9{-9} = -1{-9}$ $-5x = -10$ $\dfrac{-5x}{{-5}} = \dfrac{-10}{{-5}}$ ${x = 2}$ Now that you know ${x = 2}$ , plug it back into $\thinspace {y = 3x-3}\thinspace$ to find $y$ ${y = 3}{(2)}{ - 3}$ $y = 6 - 3$ $y = 3$ You can also plug ${x = 2}$ into $\thinspace {4x-3y = -1}\thinspace$ and get the same answer for $y$ : ${4}{(2)}{ - 3y = -1}$ ${y = 3}$